Optimal resource allocation for multicast sessions in multi-hop wireless networks - Discussion by Crowcroft, J, Allsop, R, Smith, A, Varaiya, P, Gibbens, R, Bell, M, Key, P, Borst, S, Reinert, G, Briggs, K, Mondragon, R, Zhou, S, Srikant, R, Wischik, D, Atkinson, R, Smith, M, Patriksson, M, Ralph, D, Kirby, H, Brooke, J, Kelly, F, Odlyzko, A, Raina, G